Apparatus for producing bundles of optical fiber

ABSTRACT

Producing bundles of optical fiber by winding successive layers of the fiber in the same spiral direction on winding apparatus. The apparatus includes a main winding drum over which a second coaxially aligned hollow drum of larger diameter is moveable along the common axis of the drums. A motor-driven lead screw coupled to the hollow drum is actuable to move the hollow drum back and forth along the winding surface of the main drum from one end to the other thereof while both drums are rotated by a common drive shaft. With the hollow drum positioned at one end of the main drum, the fiber is wound from the opposite end of the main drum along its surface up to and onto the hollow drum. Without interruption of the winding process, the fiber is returned to the beginning of the winding surface of the main drum by moving the hollow drum up to the starting point of the first winding. The hollow drum is then retracted causing the fiber to engage the first fiber winding on the main drum and continue therealong in the same spiral direction. A guide roller moved back and forth parallel to the common axis of the drums controls the pitch of spiral winding.

Elite States [72] lnventors KazuyoshiNagao;

Akihiko Katsura, both of Yokohama,

Japan [2]] Appl. No. 861,597 [22] Filed Sept. 29, 1969 [45] PatentedAug. 31, 1971 [73] Assignee American Optical Corporation Southbridge,Mass.

[54] APPARATUS FOR PRODUCING BUNDLES 0F OPTICAL FIBER 2 Claims, 4Drawing Figs.

[52] U.S.Cl 242/18 R,

242/ l 8 G [51] lnt.Cl B65h 54/10 [50] Field of Search 242/18, 186,43,l58;65/2, 11, 11W; 350/96 B [56] References Cited UNITED STATES PATENTS3,229,925 1/1966 Ballmer 242/18 G 3,248,063 4/]966 Sheldon et al. 242/18G 3,506,208 4/1970 Davy et a1 242/18 Primary Examiner-Stanley N,Gilreath Att0rneysWilliam C. Nealon, Noble S. Williams and Robert J.Bird ABSTRACT: Producing bundles of optical fiber by winding successivelayers of the fiber in the same spiral direction on winding apparatus.The apparatus includes a main winding drum over which a second coaxiallyaligned hollow drum of larger diameter is moveable along the common axisof the drums. A motor-driven lead screw coupled to the hollow drum isactuable to move the hollow drum back and forth along the windingsurface of the main drum from one end to the other thereof while bothdrums are rotated by a common drive shaft. With the hollow drumpositioned at one end of the main drum, the fiber is wound from theopposite end of the main drum along its surface up to and onto thehollow drum. Without interruption of the winding process, the fiber isreturned to the beginning of the winding surface of the main drum bymoving the hollow drum up to the starting point of the first winding.The hollow drum is then retracted causing the fiber to engage the firstfiber winding on the main drum and continue therealong in the samespiral direction. A guide roller moved back and forth parallel to thecommon axis of the drums controls the pitch of spiral winding.

PATENTEU mm mm 35021445 FIG.|.

F|G.2. FIG.2A. (PRIOR ART) VIN'I'OIS IN KAZUYOSHI N O AKIHIKO KATS BY IATTOINBY APPARATUS FOR PRODUCING BUNDLES F OPTICAL PEER BACKGROUND OFTHE INVENTION 1. Field Of The Invention Fiber optics with particularreference to apparatus for producing bundles of optical fiber.

2. Description Of The Prior Art In the production of bundles of opticalfiber intended to be used as image-transmitting devices, there is therequirement that corresponding opposite ends of fibers in the bundle bearranged in identical geometric patterns so that images transmitted bysuch devices will be substantially geometrically identical to the imagesreceived thereby. While tedious hand packing and aligning operations arecommonly used to form fiber optical image transfer devices, varioustechniques and apparatuses have been devised for expediting the packingand aligning operations. In addition to the use of fiber holding andaligning fixtures, jigs and the like, a prior art technique for formingimage-conducting fiber bundles involves the winding of ribbons of fiberon a rotatable drum as shown and described in U.S. Pat. No. 3,03 3,731,for example. Therein a multiplicity of ribbons of one fiber thicknessare formed and stacked one within another, secured together throughout asection of their length and cut across the secured section to formgeometrically identical opposite end faces of the resulting fiberbundle.

In having to make and use a multiplicity of ribbons of only one fiberthickness and hand stack these ribbons with their spiral directionsaligned parallel to each other in order to produce the geometricallyidentically patterned end faces of the resulting fiver optics, manytedious and time-consuming operations are not avoided.

The present invention, in its relationship to apparatus for making fiberoptic bundles, avoids the heretofore troublesome and time-consumingmultiplicity of operations involved in the manufacture ofimage-conducting bundles of optical fiber by making it possible to winda complete multilayer bundle of fiber in one continuous operation withall convolutions of the fiber having the same spiral direction as isrequired for producing identically geometrically patterned opposite endfaces by cutting across the bundle.

SUMMARY OF THE INVENTION In producing image-transmitting optical fiberbundles, it is necessary to arrange the lengths of fiber in a mannersuch as is shown in FIG. 2 of the accompanying drawing wherein the fiberlengths are aligned parallel to each other as a result of winding theconvolutions of fiber in the same spiral direction rather than inalternately opposite spiral directions as shown in FIG. 2a. The latterresults from a prior art practice of winding successive layers of fiberback and forth across each other.

According to the present invention, optical image-transmitting bundlesformed of layers of fiber convolutions all having the same spiraldirection'are produced in large quantities in an uninterrupted,high-speed operation from a continuous optical fiber. A main windingdrum upon which the optical fiber bundles are wound is coaxially alignedwith a second hollow drum moveable in an axial direction over the maindrum. A motor-driven lead screw coupled to the hollow drum is used tomove the hollow drum back and forth along the winding surface of themain drum from one end to the other thereof simultaneously with rotationof the two drums by a common drive shaft. The winding operations isinitiated with the hollow drum positioned adjacent one end of the maindrum whereupon the fiber is wound from the opposite end of the main drumalong its winding surface up to and onto the hollow drum. Withoutinterruption of the winding process, the fiber is then returned to thebeginning of the winding surface of the main drum for the winding of asecond layer of fiber directly upon the first winding by moving thehollow drum, now carrying the fiber, over the main drum up to thestarting point of the first winding. The hollow drum is then retracted,causing the fiber to engage the first wound layer thereof on the maindrum and continue winding therealong. This operation is repeated withoutinterruption until a desired number of layers of fiber is produced onthe main drum. A guide roller moved back and forth parallel to thecommon axis of the two drums controls the direction and pitch of spiralwinding.

In view of the fact that successive layers of fiber windings increasethe effective winding diameter of the drum and normally correspondinglyincrease the tension on the fiber being wound with the result of thefiber diameter being reduced by stretching should it be supplied to thewinding apparatus directly from a heated source of core and claddingmaterials, it is contemplated that cushions be provided in the windingsurface of the main drum over which the fiber bundle is wound. By suchmeans, variations in tension and thinning of the fiber or the effect ofexcessive tightening of fiber convolutions of successive layers thereofis avoided.

DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic illustration, inperspective, of a preferred embodiment of optical fiber windingapparatus;

FlG. 2 is a fragmentary perspective illustration of the type of opticalfiber alignment obtained by use of the apparatus illustrated in FIG. 1;

FIG. 2a is a fragmentary perspective illustration of the type of opticalfiber alignment resulting from the practice of a prior art multiplelayer winding technique; and

FIG. 3 is a diagrammatic illustration of a modification of the apparatusillustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In referring more particularlyto FIG. 1 it will be seen that the illustrated optical fiber windingapparatus includes a lead screw 3 driven by a reversible motor 1 throughbelt 2. Screw 3 is selectively rotatable about its axis in oppositedirections by motor 1. Internally threaded carriage 4 on lead screw 3shifts the positions of sleeves 5, 5' and 5" along shaft 9 throughconnecting members 6 when lead screw 3 is rotated. Sleeves 5, 5 and 5"are moveable freely along shaft 9 but are keyed to rotate with shaft 9whereby rotation of the shaft rotates both winding drums 10 and 12 inthe same direction. Shaft 9 and drums 10 and 12 are rotated at constantspeed by drive motor 7 through belt 8. A removable section 11 of thewinding sur face of drum l0 facilitates removal of bundles of fibersformed upon drum l0.

A roller 13 guides the fiber along winding drum 10 in a desired spiralwinding direction and pitch for producing closely packed convolutions ofthe fiber along the winding surface of drum 10.

With drum 12 positioned adjacent one end of drum 10 as illustrated byfull lines in FIG. 1, a winding of optical fiber guided by roller 13either in the form of a closely packed continuous spiral or in the formof a plurality of spaced bands as shown in FIG. 1 is formed along drum10 up to and onto drum l2. Thereupon without interruption of the windingprocedure and while the fiber is temporarily on drum 12 this drum ismoved by actuation of lead screw 3 along drum 10 over the fiber windingthereon to the position shown by dot-dash lines in FIG. 1. As this istaking place, guide roller 13 is moved back to the starting position atwhich the first layer of fiber was wound on drum l0 and drum 12 isretracted causing a second layer of fiber to be wound upon thefirst-mentioned layer thereof in the same spiral direction as that ofthe first layer. Upon completion of the winding of the second layer, theabove-described winding operation is repeated a number of timessufficient to produce a desired thickness of windings on drum 10, all ofwhich have the same spiral direction and preferably the same pitch. Inthis way, prior art alternately oppositely directed helix angles offiber windings such as are illustrated in FIG. 2a are avoided.

The windings produced on drum 10 are cemented or otherwise securedtogether throughout a transverse section thereof,

removed from the drum and cut transaxially through the secured sectionto form image'conducting bundles of fiber having identicallygeometrically patterned opposite end faces. Removal of section 11 fromdrum 10 facilitates the removal of fiber windings from the drum. It isalso contemplated that a sheet of thin plastic material may be wrappedaround drum l and the fiber windings formed thereover to furtherfacilitate removal of the fiber windings from the drum by sliding theplastic wrap ofi the drum with the fiber windings carried along With it.

- In order to avoid undue increases in tension upon the fiber beingwound as the effective winding diameter of drum increases according tothe number of layers of fiber being wound thereupon, resilient rubbercushions or air pillows 14 may be placed about the circumference of thewinding surface of drum 10 as diagrammatically illustrated in FIG. 3. Inso doing, the aforesaid increase in tension upon the fiber will beessentially negated by compression by the cushions in response to forcesexerted thereagainst by the fiber when these forces exceed thoseproduced during the winding of the first fiber layer on drum 10.

It is pointed out that cushions 14, FIG. 3, may be designed to have anonlinear spring constant for producing the abovedescribed result oftheir use or, in the case of their being air pillows or the like,automatic external control of air pressure therewithin may be providedto produce a desired nonlinear compression constant. It is furtherpointed out that the present invention contemplates the use of windingdrums l0 and 12 which are noncircular, e.g. polygonal.

We claim:

1. Optical fiber winding apparatus comprising:

a main winding drum;

a rotatable drive shaft upon which said main drum is mounted forrotation with the drive shaft about its axis;

a second hollow winding drum mounted on said drive shaft coaxially withsaid main drum, said diametrically larger than said main drum formovement over said main drum along said drive shaft;

a number of sleeves coupling said second drum to said drive shaft forrotation herewith, said sleeves being slideable along said drive shaftas a unit with'said second drum;

means for moving said sleeves and second drum back and forth along saiddrive shaft;

means for rotating said drive shaft simultaneously with said slidingmovement of said sleeves and hollow drum; and

a guide roller about which an optical fiber may be directed for windingupon said main and second drums, said guide roller being moveable backand forth along the lengths of said drums in directions parallel to thelengths of said drums.

2. An optical fiber-winding apparatus according to claim 1 includingcushions on said main drum over which said optical fiber may be directedfor winding upon said main drum.

second drum being

1. Optical fiber winding apparatus comprising: a main winding drum; arotatable drive shaft upon which said main drum is mounted for rotationwith the drive shaft about its axis; a second hollow winding drummounted on said drive shaft coaxially with said main drum, said seconddrum being diametrically larger than said main drum for movement oversaid main drum along said drive shaft; a number of sleeves coupling saidsecond drum to said drive shaft for rotation herewith, said sleevesbeing Slideable along said drive shaft as a unit with said second drum;means for moving said sleeves and second drum back and forth along saiddrive shaft; means for rotating said drive shaft simultaneously withsaid sliding movement of said sleeves and hollow drum; and a guideroller about which an optical fiber may be directed for winding uponsaid main and second drums, said guide roller being moveable back andforth along the lengths of said drums in directions parallel to thelengths of said drums.
 2. An optical fiber-winding apparatus accordingto claim 1 including cushions on said main drum over which said opticalfiber may be directed for winding upon said main drum.